1. Field of the Invention
This invention relates to novel N-(alkylthiophenyl)maleimide compounds and to compositions and methods employing such compounds in the control of rice blast.
2. Description of the Prior Art
The present invention is useful in the control and prevention of agricultural plant diseases, particularly in the control of rice blast (Piricularia oryzae) which is the most hazardous pest in rice plant. In order to prevent the rice blast, organomercury compounds such as phenyl mercuric acetate and phenyl mercuric iodide have been previously employed.
However, organomercury compounds and organometallic compounds in general are residual and accumulate in the soil of treated fields and in rice hulls and thus pose environmental as well as public health problems.
Other non-metallic organo compounds known in the art also suffer disadvantages which proscribe their use as agricultural fungicides. The most serious drawback suffered with compounds possessing fungicidal activity is their phytotoxicity to the host rice plant at desired dosage rates employed. N-(2'-methoxyphenyl)maleimide (the synthesis of which is described in Chem. Abstracts 52:9025a; see also U.S. Pat. No. 2,205,588) is an example of such a compound which, while found to be active against rice blast by the applicant, cannot be safely employed due to its high phytotoxicity to the host rice plant.